Jeni's Musings

In my last post about RDFa and HTML I talked about how one of the gulfs that separates the HTML5 and Semantic Web communities is the attitude to the resolvability of property (and class) URIs.

I’m currently experimenting with introducing the ability to automatically locate information about properties and other resources that are referenced within triples to rdfQuery, so now is a good time, as far as I’m concerned, to look more closely at what the ability to resolve properties gives you and how to avoid problems if the property URI is (temporarily or permanently) unresolvable or resolvable to something new.

I’m going to attempt to answer:

• How do or might applications use property and class URIs?
• How can data and ontology publishers assist them in doing so?
• What should frameworks (such as rdfQuery) do to help application developers?

I wrote previously about a visualisation using Home Office data to navigate around categories of offences. The second interesting set of data from the Home Office that I found, tucked away in a small link on a page about Crime Reduction Toolkits was a spreadsheet of recorded crime statistics between 1898 and the present day. Each column is a different category of offence (I won’t say class because they don’t map onto the Classes from the spreadsheet of notifiable offences).

This time I wanted to try out the jQuery sparklines plug-in to illustrate how crime notifications have changed over time. The resulting page is available at http://www.jenitennison.com/visualisation/crime.html; here’s a screenshot for Bigamy:

The Home Office recently opened up some of its data, mostly in the form of PDF reports and Excel spreadsheets. Right after, I went on holiday and offline (!) for a week, so I set myself the task of putting together some visualisations of the data using two client-side visualisation libraries that I liked the look of:

• jQuery sparklines which I think look simply gorgeous and which follow the jQuery tradition of being incredibly easy to put on a page
• the JavaScript InfoVis Toolkit (JIT) which can be used to create some very attractive and interactive visualisations for hierarchical information

As a quick summary, I ended up with solutions that use an HTML page with rdfQuery code that pulls in static RDF/XML files and performs queries on them to create the particular formats that the two client-side libraries require.

The first one I’m going to talk about is a visualisation of types of offences using JIT. There’s a screenshot below to give you a flavour, but you’d be better off actually visiting the page because it’s interactive: mousing over and clicking on the labels enables you to navigate around the hierarchy.

If you’re anywhere near Oxford on the weekend of the 11-12th July, and are interested in parsing, querying and manipulating RDF(a) in a browser, come along to the rdfQuery Dazzle (hack days). The official page lists some of the things we might work on:

• Applications: widgets, adding to existing RDFa sites
• Core development: documentation, packaging, microformats, named graphs, and ontologies
• Interfaces: Talis change markup, N3 and Turtle, and SPARQL

It’s free to attend, you can come for either or both days, and refreshments, entertainment and wifi will be provided, so register now!

Earlier this week I presented at SWIG-UK about rdfQuery. rdfQuery is a set of plugins that I’ve developed for jQuery in order to support RDFa parsing, querying and generation. There are a bunch of other Javascript libraries for RDFa around, such as Mark Birbeck’s Ubiquity RDFa and Ben Adida’s RDFa library. What I’ve really tried to do with rdfQuery is tie it in with the “Write Less, Do More” philosophy of jQuery and provide a neat, elegant API. At least that’s the aim!